1. Ambipolar ferromagnetism by electrostatic doping of a manganite.
- Author
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Zheng, LM, Wang, X Renshaw, Lü, WM, Li, CJ, Paudel, TR, Liu, ZQ, Huang, Z, Zeng, SW, Han, Kun, Chen, ZH, Qiu, XP, Li, MS, Yang, Shize, Yang, B, Chisholm, Matthew F, Martin, LW, Pennycook, SJ, Tsymbal, EY, Coey, JMD, and Cao, WW
- Abstract
Complex-oxide materials exhibit physical properties that involve the interplay of charge and spin degrees of freedom. However, an ambipolar oxide that is able to exhibit both electron-doped and hole-doped ferromagnetism in the same material has proved elusive. Here we report ambipolar ferromagnetism in LaMnO3, with electron-hole asymmetry of the ferromagnetic order. Starting from an undoped atomically thin LaMnO3 film, we electrostatically dope the material with electrons or holes according to the polarity of a voltage applied across an ionic liquid gate. Magnetotransport characterization reveals that an increase of either electron-doping or hole-doping induced ferromagnetic order in this antiferromagnetic compound, and leads to an insulator-to-metal transition with colossal magnetoresistance showing electron-hole asymmetry. These findings are supported by density functional theory calculations, showing that strengthening of the inter-plane ferromagnetic exchange interaction is the origin of the ambipolar ferromagnetism. The result raises the prospect of exploiting ambipolar magnetic functionality in strongly correlated electron systems.
- Published
- 2018